But possibly these lakes are not asleep after all! They may be only playing possum; or hide and seek. There _are_ mountain lakes that play hide and seek. That is to say, they hide and _you_ seek; and often you don't find! They are so small that, surrounded as they are by trees, tall and thickly set, even the ducks pass them by. The glaciers that made them seem to have hidden them, as the robins did the babes in the wood. The glaciers did this, not by heaping leaves over them, but by piling up stones and soil around them. They are encircled by moraines, and on the moraines grow the trees that hide the lakelets even from the sharp eyes of the ducks. [Illustration: A LITTLE GIRL'S PICTURE OF A FAMOUS SWISS LAKE This picture of the lake of the Great St. Bernard was taken by Phyllis M. Pulliam, who sent it to _St. Nicholas_ with a long, enthusiastic letter, such as only school-girls know how to write. Among other things she met a great St. Bernard dog that had saved more than fifty lives. ] Mountain lakes are usually as clear as crystal, and, like perfect mirrors, reflect the outlines and coloring of the clouds and the neighboring peaks. They are apt to contain mica and feldspar ground out of the granite rock by the glacier that made their basins. Then the sunlight falling on these rock particles gives them the color of jade or Nile green, or dark green like a peacock's tail. They are constantly changing color with the changing angles of the light from morning until sunset; and under the passing clouds and the rippling of the winds. The deeper lakes are dark blue in the deepest parts, turning to green in the shallow waters near shore where the yellow of the sun rays and the sand mixes most with the blue of the waters.[38] [Footnote 38: Van Dyke: "The Mountain."] THE MYSTERY IS IN THE SECRET PASSAGE In Florida there are sister lakes so sympathetic that their waters rise and fall together. One responds to the mood of the other as promptly as your right eye waters in sympathy when you get a grain of dust in the left. The reason for this goes back to the days when the corals helped build Florida. They did this by leaving their "bones" on the coral reefs when that part of North America was in the making. These remains formed limestone. Then, in this limestone, "sink holes" were formed on the surface leading to underground passages, just as they do over the land surface in the cave regions of Kentucky. These sink holes often fill with water and form little lakes. These lakes, being connected by the underground passages, rise and fall together. It looks very strange, even when you know the secret of it; and still stranger when you don't. Yet I shouldn't be surprised if a bright boy or girl seeing two lakes rising or falling together would suspect the underground connection; for, of course, we all know about springs and their underground channels. But what would you say to this: